Patients undergo external beam fractionated regional radiotherapy once daily 5 days a week for 6 weeks and receive concurrent oral temozolomide once daily for 6 weeks. Patients also receive bevacizumab IV over 30-90 minutes every 2 weeks beginning on the first day of radiotherapy and continuing in the absence of disease progression or unacceptable toxicity. Beginning 2-5 weeks after completion of radiotherapy, patients receive oral temozolomide on days 1-5. Treatment with temozolomide repeats every 28 days for up to 24 courses in the absence of disease progression or unacceptable toxicity.